Image courtesy of NASA/JPL-Caltech The Mars mission – technology for another world We did not find any little green men on Mars, but we did find dried out lakes and river beds. The NASA missions keep discovering new secrets of the red planet. Always on board: Reliable DC motors by Swiss drive specialist maxon motor.
erhaps mankind will soon start its first colo- tions – extreme cold, heat, impact, and vibration. nies on Mars. They will mine the ground for We have been able to use this experience to im- Pice, use it as drinking water, and plant veg- prove our products on Earth many times.” etables in greenhouses. And when it gets dark, they will look at the night sky, towards Earth, The historic breakthrough where the foundation for their mission was laid Currently we are still sending robots on the long ago. An unrealistic scenario? Not at all. long journey to Mars. They explore the barren The research on Mars has advanced immense- landscape, investigate rock samples, and take ly in the past 20 years and precision drives by breathtaking photos. The first of these was So- maxon motor have made an important contribu- journer, a rover with six wheels, which landed tion. In four missions by the US space authority on July 4, 1997. It was a historic moment, as all NASA, products of the Swiss company reached previous attempts to send a vehicle to Mars have the surface of Mars. The data collected over the failed. Sojourner was small and weighed only course of these projects is bringing us closer and 10.5 kilogram. For almost three months, it wan- closer to the goal of a manned mission to our dered across the sandy landscape and sent back neighboring planet. maxon motor also gains im- images and data – much longer than planned. portant new insights with every flight: CEO Eugen The vehicle was driven by electrical maxon DC Elmiger: “In space, our brushed and brushless motors. These high-quality drives with ironless DC motors are confronted with very harsh condi- windings were installed at the wheels and were
1 Application story used for the steering as well as for the operation of the scientific equipment. For four years, maxon engineers worked with the NASA employees to make the project a reality. Its success fascinated the entire world. Since then, the terms “maxon” and “Mars” have been closely linked. Yet that was only the start.
The twins on the red planet Driven by the success of the Sojourner mission, NASA soon started planning the next trip to Mars. This time, two identical rovers were to be sent up simultaneously: Spirit and Opportunity. They were significantly larger than their predecessors (around 185 kg) and equipped with more ad- vanced technology. The rovers were able to take photos, brush and scrape rocks to reveal fresh surfaces for study. Their mission: Find evidence that there used to be water on Mars, and thus, maybe, even life.
“Today, ten years after its landing, Opportunity is still The volume of Mars, our neighboring planet, is only a seventh of that of the Earth. Its surface is a wasteland covered in rocks and red dust. An unre- traveling the surface al landscape, today absolutely hostile to life. Breathing is impossible: The planet has only a very thin atmosphere that consists mostly of carbon di- of Mars.” oxide. The average temperature on the surface is around –55 °C. Mars has many canyons and volcanoes. The largest is Olympus Mons, with a height of 27 km, which makes it the tallest mountain in our solar system. (Image: maxon motor) The two vehicles exceeded all expectations. Their expected service life was three months. However, six years passed before Spirit sent its last sig- nal to Earth. Its brother Opportunity is still going strong even today, ten years later. Since the land- ing, it has traveled more than 40 km. Despite sand storms and temperature fluctuations from −120 to +25 degrees, the maxon DC motors are also still performing reliably. Each rover is equipped with 35 of these precision drives, which are re- The hunt for the hidden ice sponsible for driving the six wheels, the steering There is still ice on Mars, for example at the two mechanism, the RAT (rock abrasion tool), the ro- polar caps. The researchers assumed that there botic arm, and the cameras. In addition, 8 maxon is more ice in other regions – below the surface motors were used in the lander. of Mars. Phoenix was sent to prove this theory. It landed on Mars in 2008. Unlike its predecessors, Opportunity's great birthday present it was a stationary space probe. After just a short Opportunity is still a source of great joy to the period, it provided the desired evidence. It used scientists on Earth, even though it is starting to its arm to scrape away soil at the surface to re- suffer from some old-age ailments. In January veal bright water ice below. This discovery made 2014, just in time for its ten-year anniversary, it the maxon motor team in Sachseln jump with joy. found traces of water in the rock formations it was Once more, the Swiss motor specialist had been investigating at the Endeavour crater. In addition, a partner in the NASA mission and supplied nine the data shows that several billions of years ago, RE series precision drives. These brushed mo- this was the site of a lake, possibly with good tors with special ball bearings were used to de- conditions to support organic life. ploy the solar panels on Phoenix.
2 Application story A new star on Mars is standing on Mars himself. A feeling that could The researchers could not and would not rest become reality in the near future: While there are on their laurels. They embarked on a new, dar- still many obstacles to be overcome before the ing project and planned to send another rover first manned flight can depart to Mars, the NASA to Mars. This one exceeded all previous dimen- rovers have already paved the way. sions. Curiosity, the new star in the rover squad, weighed 900 kg and had the size of a compact car. It landed on the red planet in August 2012. Equipped with a robotic arm that can drill and de- liver samples to an onboard laboratory, it is on a The Mars adventure continues! constant quest to understand if Mars ever was ESA, the European Space Agency, is plan- capable of harboring life. Radionuclide batteries ning its own Mars mission in cooperation ensure a reliable energy supply. maxon MR en- with the Russian agency Roscosmos. Un- coders enable control of the motors in the elec- der the name ExoMars, a probe will be tromechanical joints. launched towards our neighboring planet in Since its landing, Curiosity has made quite a 2016. A Mars rover is to follow two years few tracks in the red sand and collected valuable later. It will be somewhat smaller than Cu- data to provide the scientists with new knowledge riosity, but it will come with a drilling unit about Mars. It discovered elements such as hy- that can retrieve rock samples from a depth drogen, oxygen and carbon, the so-called build- of two meters. Samples will be analyzed ing blocks of life, under the surface of Mars. This directly in the rover. Once again, maxon is a strong indication that our neighbor ing planet motor is involved as mission partner and used to fulfill the prerequisites for life. Curiosity will supply precision drives from the DCX also shot landscape photos with such an impres- series for the ExoMars rover. sive resolution that the viewer feels almost like he
Author: Stefan Roschi
More information: maxon motor ag Brünigstrasse 220 P.O.Box 263 CH-6072 Sachseln
Phone: +41 41 666 15 00 Fax: +41 41 666 16 50 www.maxonmotor.ch Twitter: @maxonmotor
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3 Application story maxon drives in the Mars missions
Sojourner Spirit/Opportunity The first Mars rover landed on July 14, 1997. The twin rovers landed on Mars in January 2004. Service life: Three months. maxon supplied Spirit collected data for six years, Opportunity is eleven DC motors with a diameter of 16 mm for still active today. Both rovers were equipped with the drives, the steering, and the scientific devices. 35 maxon motors each. With a few modifications, the DC motors have no problem withstanding tem- perature fluctuations from− 120 to +25 °C.
Phoenix Curiosity A stationary Mars probe that landed on Mars on The star of the rover squad landed on Mars in Au- May 25, 2008. With its robotic arm, it took rock gust 2012. It surpasses its predecessors not only samples from the ground and analyzed them. technologically: Curiosity is the size of a small car, Service life: Five months. maxon supplied nine weighs 900 kg, and is powered by a radionuclide brushed DC motors of type RE 25, with special battery. maxon motor supplied components for the ball bearings for aligning the solar panels. precision encoders installed on the drive axles.
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